Thick steel plates of curved or irregular edge contour present a welding problem as regards accurate retracing of the machine over the irregular path during successive passes of the machine. The present invention provides an electrical probe device that automatically oscillates back and forth across the gap between the work pieces during the first pass of the welding machine therealong. The oscillating probe develops a signal of varying intensity related to the position of the gap. The minimum value of the generated signal may be used to center the welding torch that follows the probe; the minimum value of the signal may also be used as input to a computer that stores the signal for subsequently programming the machine during successive passes. The maximum value of the signal may be used to maintain the probe at a desired constant spacing above the work piece surface in spite of minor vertical oscillations of the torch that occur normally during an arc welding process.
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without payment to us of any royalty thereon.